Pneumatically operated artificial hand



Dec. 7, 1954 G. B. ROBINSON PNEUMATICALLY OPERATED ARTI FICIAL HAND Filed June :50, 195 2 INVENTOR: George 8 Robinson United States Patent PNEUMATICALLY OPERATED ARTIFICIAL HAND George B. Robinson, Napa, Calif. Application June 30, 1952, Serial No. 296,524

Claims. (Cl. 31.2)

(Granted under Title 35, U. 8. Code (1952), sec. 266) The invention described herein may be manufactured and used by and for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to power-driven artificial hands and, more particularly, to pneumatically actuated artificial hands.

Heretofore artificial hands have been actuated by cables connected to various parts of the body, such as the shoulders, or have been actuated by power-driven means such as pneumatic devices which are energized by the muscles of the arm to which the artificial hand is connected. In either event the arrangement has been awkward. It is therefore an object of this invention to provide an artificial hand wherein the power-driven means, such as a pneumatic actuating means, is merely controlled or triggered by the muscles of the arm to which the hand is attached.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a plan view of a device embodying the invention;

Fig. 2 is a sectional view through one of the fingers of the artificial hand and its accompanying power-driven actuating means; and

Fig. 3 is a view showing the resilient wrist member upon which the fingers are mounted.

Briefly, this invention comprises an artificial hand which is actuated by a power-driven device and which has an element for controlling the flow of power to the power-driven device, this control element being connected through a control cable to a muscle of the amputee so as to be operated by that muscle. In a preferred illustrated embodiment, the device is pneumatically driven and the control element is a valve connected to a muscle in the forearm. The cable is attached to the muscle by means of an eyelet formed in the muscle by a cineplastic operation. In this operation the muscle is slit and a tube of skin is positioned in the slit. This piece of skin grows integral with the muscle to form an eyelet through which a pin can be inserted to which pin the control cable is attached. The muscle so adapted is called a cinemotor. Contraction of the muscle displaces the control cable longitudinally. Since the valve, which is the control element of the pneumatically-driven device, is connected to the cable, the device is triggered or set into operation by the muscle contraction and the hand is actuated which, in the illustrated embodiment, involves flexing of the fingers.

For a detailed description of a preferred embodiment, reference is now made to the drawings and particularly to Fig. 1. This embodiment comprises a Wrist member gradually indicated at 1, including a finger mount 2 of rubber-like material held between metal pieces and including also a threaded portion 5 for attaching the hand to the bucket or socket carried by the stump of the amputee. The hand includes fingers 6 through 9, having hollow stem-like portions 10, which fit firmly into sockets 11 in the element 2, thus giving the fingers a more or less resilient mount. For added resiliency, the thumb 12 is mounted over a tongue 13 rather than in a socket. Each of the fingers includes, as shown in the detail drawing of Fig. 2, a metacarpal piece indicated generally at 15,

2,696,010 Patented Dec. 7, 19 54 to which is articulated a first phalange 16, to which in turn, at its distal extremity, is articulated a second or ungual phalange 17. The metacarpal piece 15, which is rigidly connected to the stem portion 10, includes a pneumatic piston and cylinder arrangement comprising a piston 19,, reciprocable in a cylinder 20 to flex the phalanges of the finger. For controlling the flow of air in the cylinder, there is provided an inlet valve 21 and an outlet valve 22, which can conveniently be, as shown, of the type used in conventional pneumatic automobile tires. The high pressure side of inlet valve 21 lies generally in a chamber 23, Which is sealed ofl from access to the atmosphere by diaphagm 24 and to which air under pressure can be admitted from a source, not shown, through a port 25 connected to the source by any convenient tube or the like which can conveniently lead from opening 26 in the central element of the wrist member serving as a manifold. The valves are operated alternatively by a rocker arm type of valve actuator 27 urged by spring 28 into a position in which the outlet valve 22 is open while the inlet valve 21 remains closed. The rocker arm actuator 27 is connected by means of a cable 29 to a pin or bar 30 to which are attached the valve actuator control cables from each of the four fingers running through guide holes 31 in the wrist member. The bar or pin 30 is adapted to be placed in the eyelet of a cinemotor. The cable 32 from the thumb valve runs through the guide hole 33 and is attached to a pin 34 to be placed in an additional cinemotor operable independently from that of the pin 30.

The piston 19 is connected through a screw 35, attached to the piston extension and passing through a slot in the stem portion 10, to a cable 36, the distal end of which is fixed at 37 to the volar region of the first phalange. A cable 38 fixed at one end as at 39 to the metacarpal portion of the hand and anchored at its other end as at 40 to the ungual phalange serves to flex the ungual phalange simultaneously with fiexure of the first phalange. This is accomplished by virtue of compelling the cable 38 to wrap itself around the cylindrical surface 41 and thus tend to shorten itself as the first phalange is flexed.

Operation To use the hand of this invention, the device is attached by its threaded portion 5 to the distal end of a bucket or socket worn by the amputee. The bars 30 and 34 are inserted in the muscle eyelet resulting from a cineplastic operation and the appropriate cables are attached to each bar. A tube leading from the compressed air generating system worn by the wearer is connected into the port 25 and the hand is then ready for use. To flex the fingers and thumb in order to grip and object, the amputee contracts the muscles carrying the bars 30 and 34. In the typical finger shown in Fig. 2 this causes the cable 29 to rotate the valve rocker arm 27 clockwise,'as viewed in this figure, against the action of the spring 28. The rocker arm thereupon releases the pressure on the stem of valve 22, allowing that valve to close and, through the diaphragm 24, tilts the valve stem of the valve 21 to open this valve, allowing air under pressure to enter through port 25 into chamber 23 and thence into the cylinder 20 to cause the piston 19 to move to the left as viewed in this figure. This motion of the piston flexes the finger phalanges through the medium of cables 36 and 38. When the amputee desires to release his grip, he simply relaxes the muscles carrying bars 30 and 34, allowing the spring 28 to return the rocker arm 27 to a position in which the valve 21 is again free to close and the valve 22 is opened. This allows the compressed air within the cylinder 20 to escape through the open valve 22. Thereupon, the phalanges are free to return to their extended position. The return of the fingers to extended position automatically draws back the piston 19 toward the right, as viewed in Fig. 2, through the medium of cable 36 and pin 35.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. An artificial hand comprising power-driven means for actuating the fingers of said hand; means for controlling the flow of power to said power-driven means; and means adapted for actuation by a cinemotor muscle for operating said control means; said third named means including a pin for insertion in a canal in said cinemotor muscle and means connecting said pin to said powerflow-controlling means.

2. The device of claim 1 wherein said hand includes a thumb and fingers and wherein said device includes a first cinemotor means for governing actuation of the thumb of said hand and a second cinemotor means operatable independently of said first cinemotor means for governing actuation of the remaining fingers of said hand.

3. The device of claim 1 wherein said power-driven means are pneumatically driven.

4. The device of claim 3 wherein said power-driven means includes a pneumatic piston and cylinder arrangement for flexing the fingers of said hand and said powerflow-control means includes valves for controlling air flow in said cylinder, and said cinemotor means includes a mechanism for operating said valves comprising said pin and said connecting means.

5. An artificial hand comprising a wrist element ineluding a portion for resiliently mounting a plurality of fingers; a plurality of fingers including a thumb mounted on said wrist element; mechanism for flexing each finger comprising a pneumatic piston and cylinder; means connecting said piston to a phalange of a finger whereby motion of said piston in said cylinder flexes said finger; an air inlet valve and an air outlet valve for each cylinder; a rocker arm for alternatively operating said valves; and means for actuating said rocker arm adapted for connection to a muscle eyelet; the mechanism for actuating said thumb being operable independently of the mechanism for operating said fingers.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,442,530 Eberle June 1, 1948 FOREIGN PATENTS Number Country Date 78,793 Norway Apr. 4, 1950 297,284 Germany Mar. 31, 1917 318,851 Germany Feb. 16, 1920 828,291 Germany Jan. 17, 1952 

